Taiga = Automatically detects the anime videos you watch on your computer and synchronizes your progress with online services(MyAnimeList/AniList/Kitsu). It helps you manage your anime library, discover new series, share watched episodes and download new ones.
How to use in myanimelist because MAL API is down = [Taiga → Kitsu → MAL]
First you must export MAL anime list and create kitsu account and import to kitsu (Note that Kitsu is able to automatically sync your library updates to MyAnimeList. Visit the Settings → Export page to set it up) Change from the horrible default smiley ratings to MAL ratings in your user settings. [Edit: Rating Type: Simple -> Advanced]

KawAnime = Lets you know the latest releases according to your preferred fansubs, and lets you download them easily with just a click.ShokoAnime = Automate Your Anime Collection.

Shukofukurou = Anime and Manga library management and title discovery application for macOS that allows Mac users to manage their Myanimelist, Kitsu and AniList lists in one place.

Trackma = Trackma aims to be a lightweight and simple but feature-rich program for Unix based systems for fetching, updating and using data from personal lists hosted in several media tracking websites.

Shukofukurou for iOS = A light weight and easy to use Anime and Manga library management and title discovery application for iOS that allows iPhone and iPad users to manage their Kitsu and AniList lists in one placeTaiYaKiAnime = Stream anime and synchronize with your MyAnimeList on iOS devices.NineAnimator = A simple yet elegant way of waching anime on your favorite anime websites.